1. Field of the Invention
This invention relates to prosthodontic implants for rigidly securing a prosthesis in a natural or a prepared jawbone socket.
2. Description of the Prior Art
Presently there exist many types of dental implants designed to enable a prosthesis such as a crown replacement to be rigidly secured to the jawbone. Probably the most common type of dental implant consists of a threaded pin which is dimensioned to threadably engage the socket of a recently extracted tooth. U.S. Pat. Nos. 3,589,011 and 4,234,309 and German No. 2,255,916 are illustrative examples of such threaded-type implants. The primary disadvantage to the threaded implants in their tendency to loosen within the socket. The implant then has to be removed and replaced by a larger diameter implant. For obvious reasons, these threaded-type implants have not become widely accepted in the art.
U.S. Pat. No. 3,835,033 discloses another type of implant which is designed to be inserted within the socket or alveolar cavity of a recently extracted tooth. More particularly, this type of implant comprises two posts which are inserted into the socket. A plurality of fins and spacers are alternatively slipped onto the posts extending from the socket, with the length of the spacers determining the distance between adjacent fins. The total number of fins and spacers are selected to achieve the desired height of the implant and correspondingly, the amount by which the implant extends from the socket. The implant is left within the socket for a period of time sufficient to enable the bone structure to grow between the adjacent fins. The prosthesis is then connected to the exposed end of the post. A primary disadvantage to this particular implant is the requirement that the implant be assembled piece by piece into the socket of the extracted tooth. This not only increases the difficulty of installing the implant but also increases the likelihood that one of the component pieces will be aspirated by the patient. Moreover, the numerous separate pieces, each of which must be machined to extreme tolerances, increases the overall cost of manufacture of these dental implants. For these reasons, although this type of implant overcomes many of the disadvantages of a screw-type dental implant, it has not been widely accepted in the trade due to its complexity.
U.S. Pat. No. 4,060,896 discloses a threaded-type dental implant wherein a hardenable material is disposed in the jawbone socket prior to the implant being threaded therein. The purpose of the filler material is to assure that the implant will not loosen within the socket of the extracted tooth. It is anticipated that the material will be compressed into the immediately adjacent area of the jawbone as the implant is threaded into the socket. When the material hardens, the implant will be bonded to the bone structure of the jawbone. It should be noted that the filler material must be composed of a hardenable material which will not be rejected by the body.
U.S. Pat. No. 3,672,058 illustrates another threaded-type dental implant which comprises a self-tapping conical screw. The taper of the self-tapping screw is designed such that the implant will threadably engage the socket of the extracted tooth and then threadably engage the portion of the jawbone located immediately below the socket. The socket may be filled with a hardenable resin prior to installing the implant therein. The resin is selected to increase the resistance to rejection of the implant and to avoid deformations of the jawbone.
It should be appreciated that the primary disadvantage to each of the above-described threaded-type implants is their tendency to loosen within the socket after a relatively short period of time. In order to overcome such a tendency, threaded-type implants such as the one disclosed in U.S. Pat. No. 3,474,537 have been developed which are designed to threadably engage through the lower jawbone such that the head of the implant fits against the underside of the jawbone and the terminal end of the implant extends above the jawbone and the gum tissue for providing support to a prosthesis. The head of the implant comprises a flat configuration with one or more holes extending obliquely therethrough. A threaded fastener, such as a screw, is then provided for insertion through the oblique holes to threadably engage the lower portion of the lower jawbone thereby preventing rotation of the implant. Unfortunately, this type of implant can only be utilized when securing a prosthesis to the lower jawbone, and cannot be used for securing a prosthesis to the upper jawbone. Further, a relatively tedious surgical procedure is necessary to properly install the implant.
Therefore it is an object of this invention to provide an apparatus which overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which is a significant contribution of the advancement of the dental implant art.
Another object of this invention is to provide a dental implant which is rigidly secured within the socket or aleveolar of an extracted tooth to provide a suitable foundation for a prosthesis such as a crown.
Another object of this invention is to provide a dental implant which does not threadably engage the socket or alveolar of the extracted tooth, but rather is inserted into the socket and allowed to remain therein for a period of time until the bone structure or spongy medullary of the jawbone grown about the implant thereby rigidly securing the implant in the jawbone.
Another object of this invention is to provide a dental implant having a plurality of fins which extend radially from a central post, the surface area of the fins being substantial to provide adequate support upon vertical loading of the implant.
Another object of this invention is to provide a dental implant having an elongated design with a narrow width for insertion into an artificially created hole in the jawbone.
Another object of this invention is to provide a dental implant which is particularly suitable to be inserted into an artificially created hole in the posterior maxilla to elevate the bony floor of the maxillary sinus thereby creating an equate receptor site in the bone when naturally none existed.
Another object of this invention is to provide a dental implant for insertion into an artificially created hole in the jawbone wherein fins extend radially from a cental post with the outer portions of the fins being interconnected by one or more minor posts which extend parallel to the major post.
Another object and advantage of the present invention is the provision of a boss which is integral with the proximal end of the major post, with the boss having a circumferential sleeve of ceramic material.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the present invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description describing the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.